Asymmetrische Synthese von α-Aminophosphonsäuren, III. Asymmetrische Synthese von (S)-(1-Aminoalkyl)phosphonsäure-diethylestern unter Verwendung von (+)-Campher als chiralem Hilfsreagens

Enantioselective synthesis of substituted α-aminophosphonates catalysed by d-glucose-based crown ethers: pursuit of the origin of stereoselectivity

Tuning the electronic properties of the catalyst can control the enantioselectivity of d-glucose-based crown ethers by a simple mechanism.

An Overview of Stereoselective Synthesis of α-Aminophosphonic Acids and Derivatives

An overview of all methodologies published during the last few years focused to the stereoselective (diastereoselective or enantioselective) synthesis of α-aminophosphonic acids and derivatives is reported. The procedures have been classified according a retrosynthetic strategy and taking into account the formation of each one of the bonds connected to the chiral centre.

Enantiodifferentiation of N-benzyloxycarbonylaminophosphonic and phosphinic acids and their esters using cyclodextrins by means of capillary electrophoresis

Capillary electrophoresis was successfully applied for separation of the enantiomers of N-benzyloxycarbonyl-alpha-aminophosphonic and alpha-aminophosphinic acids as well as their ethyl and phenyl monoesters with the use of a range of commercially available cyclodextrins (alpha, beta and hydroxypropyl-gamma-cyclodextrins) as chiral selectors. The dependence of effectiveness of separation on type and concentration of these chiral selectors as well as on pH of background electrolyte was examined in some detail.

Catalytic Asymmetric Synthesis of α-Amino Phosphonates Using Enantioselective Carbon−Carbon Bond-Forming Reactions

We have developed highly enantioselelctive reactions of silicon enolates with N-acyl-alpha-iminophosphonates leading to optically active alpha-amino phophonates. A copper (II)-diamine complex was shown to be effective in this reaction, and high levels of yield and selectivity were achieved. It is noteworthy that this reaction opens a way to various biologically important, optically active alpha-amino phosphonate derivatives.

Separation of aromatic aminophosphonic acid enantiomers by capillary electrophoresis with the application of cyclodextrins

The detailed studies concerning capillary electrophoresis separation of aminophosphonic acid enantiomers with various commercially available cyclodextrins are presented. The obtained results show that the separation of these stereoisomers is dependent on pH of background electrolyte, concentration of cyclodextrin as well as on the type of applied chiral selector. The separation mechanism is based on the co-operative effect of hydrogen bond type interactions enhanced by hydrophobic forces and sterical constrains between aminophosphonate and cyclodextrin. With application of elaborated method, enantiomeric baseline or partial separation of 18 alpha-aminophosphonic acids was achieved. This separation can be successfully used for routine aminophosphonic acids enantiopurity determination.

Determination of optical purity of phosphonic acid analogues of aromatic amino acids by capillary electrophoresis with alpha-cyclodextrin

A simple and efficient method for the determination of enantiomeric purity of structurally diverse phosphonic and phosphinic acid analogues of phenylalanine and phenylglycine using capillary electrophoresis is presented. These preliminary studies indicated that the enantiomer separation is strongly dependent on the structure of the aminophosphonic acid.